F50fd @ 6mp

Started Aug 28, 2007 | Discussions thread
WmAx Senior Member • Posts: 1,700
Re: Are you for real?

Well, down-sampling 'can' make noise harder to see, or even make the actual grain structure of the noise invisible, effectiveness is bound directly to the spatial frequency of the noise vs. the end target size. In this regard, down-sampling can act exactly as, and does, have the transfer function of a low pass filter. For an extreme example, take an ISO1600 image from a Fuji f30 or F31 and downsample it to 640 x 480 pixels. The fine pattern grain will be gone(it was above the spatial frequency possible in the new target file size). However, the large low frequency artifacts will still be present. In cases where low frequency noise is low, and only higher frequency noise is present, this can remove the noise pattern, at the expense of spatial frequency reduction.


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